This invention relates generally to a filter and, more particularly, to a fuel filter such as a fuel/water separator for a diesel engine or the like. Such a separator typically comprises a metal shell which houses a filter element. Fuel flows through the filter element while water and other contaminants are stripped from the fuel and accumulate in the lower end portion of the separator. Periodically, the water and other contaminants are removed from the separator by opening a drain valve at the lower end of the separator. In some separators, a water detector extends upwardly into the separator and electrically signals when sufficient water has accumulated as to require draining of the separator.
A very commercially successful fuel/water separator is disclosed in Church et al U.S. Pat. No. 4,619,764. In that separator, the filter element is housed in a sheet metal shell while water is collected in a transparent or translucent plastic bowl removably attached to the lower end of the shell. The drain valve and the water detector are attached to the lower end of the bowl.
While separators of the type disclosed in the Church et al patent have experienced wide commercial success, such separators suffer several drawbacks which result primarily from the use of the plastic bowl. The initially transparent or translucent bowl quickly becomes opaque due to contact with diesel fuel and fuel additives. In severe cases, the plastic actually cracks or crazes. Heat causes the bowl to distort, and road hazards such as thrown rock or salt can puncture the bowl. Any or all of these weaknesses can lead to leaking of the separator, thereby contaminating the environment and endangering the safety of the vehicle operator.
Separators of the type disclosed in the Church et al patent also lack static and hydrodynamic strength. Such separators are prone to leakage whenever internal static pressure approaches 60 psi. and tend to fail after less than 50 cycles when subjected to pressure surges of 0-100 psi. at 2 Hz.